Alonso: Top five are Michael, Fangio, Senna, Prost, Lewis

The pair were fractious teammates at McLaren in Hamilton’s 2007 debut season, with the youngster ending that campaign as runner-up and ahead of the double F1 world champion Alonso who then left.

“I’m happy for him because he showed the talent from day one,” Alonso told reporters at the United States Grand Prix where Hamilton can seal the title if he scores eight points more than Ferrari’s Sebastian Vettel.

“He was able to win races when the car was there to win it but he was able to win races in some of the seasons when the car was not in the top of the form, like 2009,” he said.

“It’s impressive — and now it’s time to enjoy for him, so I’m happy,” added the Spaniard, who is bowing out of Formula One at the end of the year.

Hamilton will stand level with the late, great Juan Manuel Fangio if — as seems inevitable — he takes a fifth crown and becomes only the third driver to reach that mark. Michael Schumacher holds the record of seven.

Asked to list his top five world champions, Alonso — regarded as one of the best of his era — modestly declined to mention himself.”

“Probably Michael, Fangio, (Ayrton) Senna, (Alain) Prost, Lewis, probably this will be the top five, probably, that come to my mind,” he said. “But it’s difficult to compare different times and different ways to win those championships.

“Lewis winning five now and being the same as Fangio...it’s a great achievement and if one had to do that in our generation, I’m happy that it’s Lewis because he showed the talent and he showed the commitment.”

Hamilton, who has won four races in a row and six of the last seven, refused to take anything for granted even if he is now 67 points clear of Vettel with four races — worth a total 100 points — remaining.